# CertGuard (remote · certguard.mike-tusa.workers.dev)

Free SSL/TLS certificate checker: expiry, chain trust, hostname match, TLS version, A/B/C/F grade.

- Trust score: 79/100 (medium)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- remote · `certguard.mike-tusa.workers.dev`: 79/100 (this document), [markdown](https://verifymcp.io/servers/dev-workers-mike-tusa-certguard-certguard/certguard.md), [page](https://verifymcp.io/servers/dev-workers-mike-tusa-certguard-certguard/certguard)

## Channel facts

- Endpoint: `https://certguard.mike-tusa.workers.dev/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.3.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Endpoint Security**: 69/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Nothing on it is marked destructive, but we can't show that an anonymous caller can only read: full credit needs the server to list at least one tool and every tool to be verifiably read-only. We use a best-effort check of tool names and descriptions to tell read-only tools from tools that change things, so some genuinely read-only tools may not get full credit. Names that start with a read verb (get, list, read, search and similar) and accurate readOnlyHint annotations help. Meet that to earn full credit, or require authorisation.
  - HTTPS enforcement could not be verified: the plaintext port answered with HTTP 405, which proves neither a plaintext path nor enforcement.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 65/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 482 tokens (~482/item across 1 items; 1 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 87/100
  - Stability observed for 26 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 1 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 2 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the CertGuard MCP server?

CertGuard is a hosted endpoint at https://certguard.mike-tusa.workers.dev/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http dev-workers-mike-tusa-certguard-certguard 'https://certguard.mike-tusa.workers.dev/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "dev-workers-mike-tusa-certguard-certguard": {
      "url": "https://certguard.mike-tusa.workers.dev/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "dev-workers-mike-tusa-certguard-certguard": {
      "type": "http",
      "url": "https://certguard.mike-tusa.workers.dev/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.dev-workers-mike-tusa-certguard-certguard]
url = "https://certguard.mike-tusa.workers.dev/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dev-workers-mike-tusa-certguard-certguard": {
      "type": "remote",
      "url": "https://certguard.mike-tusa.workers.dev/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dev-workers-mike-tusa-certguard-certguard --url 'https://certguard.mike-tusa.workers.dev/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  dev-workers-mike-tusa-certguard-certguard:
    url: "https://certguard.mike-tusa.workers.dev/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "dev-workers-mike-tusa-certguard-certguard": {
      "Transport": "http",
      "Url": "https://certguard.mike-tusa.workers.dev/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add dev-workers-mike-tusa-certguard-certguard -t streamable-http -u 'https://certguard.mike-tusa.workers.dev/mcp'
```

### Other

```json
{
  "mcpServers": {
    "dev-workers-mike-tusa-certguard-certguard": {
      "type": "http",
      "url": "https://certguard.mike-tusa.workers.dev/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-03 (score 79, +1)

No change was recorded against any check on this day. Stability & Change Management went from 77 to 80. That category is still filling its 30-day observation window: 23 days of observed history at the previous scan, 24 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-11-01 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 70 to 73. That category is still filling its 30-day observation window: 21 days of observed history at the previous scan, 22 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-30 (score 77, +1)

No change was recorded against any check on this day. Stability & Change Management went from 63 to 67. That category is still filling its 30-day observation window: 19 days of observed history at the previous scan, 20 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-28 (score 76, +1)

No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-26 (score 75, +1)

No change was recorded against any check on this day. Stability & Change Management went from 50 to 53. That category is still filling its 30-day observation window: 15 days of observed history at the previous scan, 16 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-24 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-22 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-19 (score 72, +1)

No change was recorded against any check on this day. Stability & Change Management went from 27 to 30. That category is still filling its 30-day observation window: 8 days of observed history at the previous scan, 9 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (1)

### `check_certificate` (~269 tokens)

Check a server's SSL/TLS certificate (expiry, chain, hostname, TLS version)

Run a live TLS handshake against host:port and audit the certificate the server presents. Returns an A/B/C/F grade and summary, expiry (days remaining), hostname match, chain completeness and trust against Mozilla's root store, negotiated TLS version and cipher suite, key type/size, findings, and a link to the full report. Revocation (OCSP/CRL) is NOT checked. Hosts on Cloudflare's own network cannot be checked live (result: isError with code live_check_unavailable, no grade); a failed handshake returns check_failed with no grade. Read-only: it only opens a TLS connection to the public host. Same engine, cache and limits as the CertGuard JSON API (GET /api/v1/check).

Input parameters:

- `host` (string, required): Hostname or public IP to check, e.g. example.com. An https:// URL is accepted and reduced to its host (and port). Private, internal and reserved addresses are rejected.
- `include_raw` (boolean): Also return the full /api/v1/check JSON (all chain certificates, SANs, handshake attempts) in structuredContent.raw. Larger output.
- `port` (integer): TCP port (default 443). Allowed: 443, 8443, 465, 993, 995.

Output parameters:

- `apiUrl` (string)
- `cached` (boolean)
- `certificate` (object)
- `chain` (object)
- `checkedAt` (string)
- `expiry` (object)
- `grade` (string)
- `gradeEstimated` (boolean): true when the result was inferred from Certificate Transparency logs instead of a live handshake
- `host` (string)
- `hostname` (object)
- `issues` (array)
- `notChecked` (array)
- `plan` (string)
- `port` (integer)
- `raw` (object): Full /api/v1/check response (only when include_raw is true)
- `reportUrl` (string)
- `revocation_checked` (boolean): Always false: OCSP/CRL status is not queried
- `source` (object)
- `status` (string)
- `summary` (string)
- `tls` (object)
- `version` (string)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/dev-workers-mike-tusa-certguard-certguard/certguard#diagnostics

## Score history

- 2026-11-05: 79
- 2026-11-04: 79
- 2026-11-03: 79
- 2026-11-02: 78
- 2026-11-01: 78
- 2026-10-31: 77
- 2026-10-30: 77
- 2026-10-29: 76
- 2026-10-28: 76
- 2026-10-27: 75
- 2026-10-26: 75
- 2026-10-25: 74
- 2026-10-24: 74
- 2026-10-23: 73
- 2026-10-22: 73
- 2026-10-21: 72
- 2026-10-20: 72
- 2026-10-19: 72
- 2026-10-18: 71
- 2026-10-17: 71
- 2026-10-16: 70
- 2026-10-15: 70
- 2026-10-14: 69
- 2026-10-13: 69
- 2026-10-12: 68
- 2026-10-10: 67

## Common questions

### What is the CertGuard MCP server?

CertGuard is an MCP server listed in the public MCP registry as dev.workers.mike-tusa.certguard/certguard. Free SSL/TLS certificate checker: expiry, chain trust, hostname match, TLS version, A/B/C/F grade. This page covers its hosted endpoint (https://certguard.mike-tusa.workers.dev/mcp).

### Is the CertGuard MCP server safe to use?

CertGuard scores 79 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the CertGuard MCP server expose?

CertGuard exposes 1 tool: check_certificate. Their descriptions and schemas cost roughly 269 tokens of context every time the server is loaded.

### Does the CertGuard MCP server require authentication?

No. We connected to CertGuard without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the CertGuard MCP server still maintained?

CertGuard is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What did VerifyMCP test on the CertGuard MCP server?

VerifyMCP ran 12 checks on CertGuard, covering TLS certificate, Authorization, HSTS header, DNSSEC and 8 more. One item could not be completed, a gap on our side rather than a finding about CertGuard: HTTPS. Supply Chain Security and Provenance & Transparency do not apply to a hosted endpoint, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.

## Links

- Remote endpoint: https://certguard.mike-tusa.workers.dev/mcp
- Website: https://certguard.mike-tusa.workers.dev/
- Changelog RSS feed: https://verifymcp.io/servers/dev-workers-mike-tusa-certguard-certguard/certguard.xml
- Changelog JSON feed: https://verifymcp.io/servers/dev-workers-mike-tusa-certguard-certguard/certguard/changelog.json
- Trust report (JSON): https://verifymcp.io/servers/dev-workers-mike-tusa-certguard-certguard/certguard.json
- HTML version of this page: https://verifymcp.io/servers/dev-workers-mike-tusa-certguard-certguard/certguard